The construction of buildings and other structures may often employ concrete masonry building materials, such as masonry units (commonly referred to as masonry blocks). For example, an individual masonry wall assembly may be constructed using either a single vertical section of masonry units (known as a “wythe”) or adjacent cavity wall vertical sections (known as a “double wythe” or “multiwythe”).
During the construction of some building structures, a set of masonry wall assemblies can be used to provide a building envelope that defines a number of exterior walls of the building structure. In such circumstances, multiwythe masonry walls are commonly employed in an effort to resist the penetration of water or other moisture to the interior of a building. For example, double wythe masonry walls usually provide an interior vertical void or cavity between an exterior vertical section and an interior vertical section of the masonry wall, thereby in part creating a drainage path for water or other moisture that penetrates through the exterior vertical section and thus reducing the likelihood that the water will pass to the interior of the building.
These double wythe masonry walls, however, are usually more costly (in both materials and labor) than single wythe masonry walls because the interior vertical section can serve as the structural wall while the exterior vertical section is erected to serve as a veneer. Conversely, a single wythe masonry wall may employ only a single vertical section of masonry units, but (depending on a number of factors) the single wythe masonry wall might be less effective at resisting moisture penetration as compared to the more costly double wythe masonry wall.
Other supplemental techniques may be implemented during the design and construction of a masonry wall in an effort to reduce the likelihood of moisture penetration through the wall. For example, the use integral water repellent admixtures in the masonry block compositions and in the mortar materials, as well as the use of concave joints when finishing the mortar and grout may contribute to moisture control. Also, the use of flashing at all horizontal interruptions of the wall surface or the use of drainage cores in the wall may contribute to moisture control. Another option to supplement the masonry wall is for a builder to apply breathable penetrating sealants or coatings on the installed wall surface, and to install drainable “weeps” at the base of the wall to facilitate the redirection of accumulated moisture in the wall cavity or masonry unit cores to the exterior. Other conventional efforts to reduce the likelihood of moisture penetration include applying air/moisture barriers along the wall, using condensation control techniques at any areas where thermal bridges in the wall may be present, and using joint reinforcement and movement joints to reduce the likelihood of cracking along the masonry wall.
While these supplemental techniques can be useful, some masonry walls are not always designed constructed using these techniques, or the workers constructing the masonry wall do not always implement these techniques in a consistent manner. Accordingly, if these supplemental techniques are overlooked or not satisfactorily executed at the construction site, the ability of the masonry wall to resist moisture penetration can be compromised.